Method of manufacturing a gas discharge panel and panel manufactured by said method

ABSTRACT

A gas discharge panel of which one or both panel plates are provided with cavities in the bottoms of which a conductor extends, which cavities and conductors are pressed in the softened material of the panel plate by means of a pressure plate in which cores in the form of balls or rods are secured, which cores comprise in the free end a groove in which the conductors are provided, which conductors remain behind in the panel plate after impression.

United States Patent [191 Gilsing [111 3,755,027 [4 1 Aug. 28, 1973 METHOD OF MANUFACTURING A GAS DISCHARGE PANEL AND PANEL MANUFACTURED BY SAID METHOD Johannes Andries Arnoldus Gilsing, Eindhoven, Netherlands Assignee: U.S. Philips Corporation, New York,

Filed: Nov. 10, 1971 Appl. N0.: 197,277

Inventor:

Foreign Application'Priority Data Nov. 19, 1970 Netherlands 7016929 US. Cl....l 156/67, 156/182, 156/219,

156/242, 156/292, 156/293, 156/298, l56/303.l, 264/272, 264/322, 40/130 R,

40/130 M Int. Cl 844d 5/00, B29d 3/00 Field of Search 156/67, 102., 104,

[56] References Cited UNITED STATES PATENTS 3,538,198 11/1970 Montebello 156/219 UX 2,958,120 11/1960 Taylor 2,470,509 5/1949 Marini 156/298 X Primary ExaminerAlfred L. Leavitt Assistant Examiner-Basil J. Lewris Attorney-Frank R. Trifari 57 ABSTRACT A gas discharge panel of which one or both panel plates are provided with cavities in the bottoms of which a conductor extends, which cavities and conductors are pressed in the softened material of the panel plate by means of a pressure plate in which cores in the form of balls or rods are secured, which cores comprise in the free end a groove in which the conductors are provided, which conductors remain behind in the panel plate after impression.

7 Claims, 9 Drawing Figures 2 Sheets-Sheet Patented Aug. 28, 1973 INVENTOR.

AGENT Patented Aug. 28, 1973 2 Sheets-Sheet 2 8 Fig.7

INVENTOR. JOHANNES A. A. GILSING AGENT METHOD OF MANUFACTURING A GAS DISCHARGE PANEL AND PANEL MANUFACTURED BY SAID METHOD The invention relates to a method of manufacturing a gas discharge panel for displaying pictures consisting at least of a lower panel plate and an upper panel plate, the upper panel plate consisting of a light-pervious material, each plate comprising a number of mutually insulated parallel strip-shaped conductors, the conductors of the lower panel plate intersecting the conductors of the upper panel plate at an angle. The invention furthermore relates to a gas discharge panel manufactured by this method. The conductors are in contact with a gas atmosphere which is contained in cavities which are present in parallel rows at the area of the points of intersection of the conductors.

The provision of a large number of cavities in a plate which consists of an insulating material is not simple, particularly if at the bottom of said cavities stripshaped conductors have to be present which must contact a gas atmosphere which is to be introduced in the cavities afterwards.

It is known per se to provide a large number of cavities in a plate by forcing balls which are partly enclosed in holes of a pressure plate in said plate.

The balls were lying loosely in the holes of the pressure plate and were kept at a given depth by means of pins.

It was not possible herewith, however, to provide conductors in the bottom of the cavities. The known method was used to manufacture projection screens having a large number of reflecting cavities of very small dimensions.

According to the invention, in a method of manufacturing a gas discharge panel for displaying pictures consisting at least of a lower panel plate and an upper panel plate, the upper plate consisting of a light-pervious material, each plate comprising a number of mutually insulated parallel strip-shaped conductors, the conductors of the lower panel -plate intersecting the conductors of the upper panel plate at an angle, all conductors being in contact with a gas atmosphere which is contained in cavities provided in parallel rows at the area of the points of intersection of the conductors, the cavities and the conductors are provided in at least one of the panel plates by means of a pressure plate in which a number of cores corresponding to the number of cavities is immovably secured, a groove which extends in the direction of the rows being provided in the free end of each core, the strip-shaped conductors being placed in said groove and being forced with the cores in the softened panel plate by the pressure plate, the pressure plate being then separated again from the panel plate, the strip-shaped conductors in the panel plate remaining behind in the bottoms of the cavities produced by the cores.

Since the strip-shaped conductors have a comparatively large length and are therefore situated in the grooves of a large number of cores which are present in a row, they are clamped sufficiently rigidly to avoid falling out of the grooves if the pressure plate, with the conductors directed downwards, is pressed on the soft panel plate. The conductors are embedded in the material of the panel plate on the bottoms of the cavities produced by the cores. Said panel plate constitutes the upper panel plate and is then placed on the lower panel plate in such manner that-the strip-shaped conductors embedded in the material of the lower panel plate intersect the conductors of the upper panel plate at an angle, usually at right angles, after which the panel plates are connected together in a vacuum-tight manner. All the cavities communicate with each other and with an exhaust tube, for example by partly etching away the conductors embedded in the surface of the lower plate so that shallow channels are formed which communicate the cavities with each other. It is also possible, however, that the separation walls between the cavities do not extend entirely up to the surface of the panelplate, so that the cavities, after the panel plates have been placed one of the other, remain in local communication with each other. The cavities can be evacuated through an exhaust tube after which the desirable gas atmosphere can be introduced into the cavities through the exhaust tube.

In order that the invention may be readily carried into effect, it will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which FIG. 1 is a cross-sectional view through a gas discharge panel manufactured by means of the method according to the invention,

FIG. 2 is a perspective view of an upper panel plate and FIG. 3 is a perspective view of a lower panel plate,

while I FIG. 4 is a sectional perspective view of an embodiment of a pressure plate, and

FIG. 5 is a plan view of the pressure plate shown in FIG. 4,-while FIGS. 6 and 7 are sectional views of other embodiments of pressure plates, and

FIG. 8 is a cross-sectional view through another embodiment of a gas discharge panel, while FIG. 9 is a perspective view of a pressure plate using cores of a different shape. I

In FIGS. 1, 2 and 3, reference numbers 1 and 2 denote a lower panel plate and an upper panel plate, respectively. A number of mutually insulated, stripshaped conductors 3 which are arranged in parallel are embedded in the lowerpanel plate 1.

Embedded in the upper panel plate 2 are mutually insulated, parallel strip-shaped conductors 4 which in this case are provided with cams or teeth 5 which extend in the discharge cavities 6. So the conductors 4 are situated in the bottoms of the cavities 6 and intersect the conductors 3 at an angle, in this case at right angles.

The cavities 6 contain a suitable gas atmosphere. The upper side of the conductors 3 is slightly etched away so that channels 7 are formed which communicate the cavities 6 with each other. The channels 7 may empty on one or both sides of the panel 1,2 into a transverse channel, not shown, which communicates with an exhaust tube which is not shown either.

At the outer edges the panel plates 1 and 2 are secured together in a vacuum-tight manner by means of a suitable cement, for example a synthetic resin, or a low melting glass. The panel plate 1 may consist of glass or a ceramic material. The upper panel plate 2 must consist of a light-pervious insulating material which can be softened, preferably glass.

A panel plate 2 can be manufactured by means of a pressure plate 8 as is shown in FIG. 4. The metal pres sure plate 8 comprises a large number of holes 10,

made, for example, by means of photographic etching. Cores in the form of steel balls 9 are immovably secured in the holes 10, for example, by soldering or welding. The balls 9 are pressed in the holes up to half of their diameter. The thickness of the pressure plate 8 is preferably equal to the radius of the balls 9 so that these can be pressed into the holes until they bear on the base plate 11 on which the pressure plate 8 may be secured. The base plate 11 may be a die. The balls 9 are commercially available in accurate dimensions.

When the balls 9 are immovably secured in the pressure plate 8, grooves 12 are sawn or milled in the rows of balls 9 which are situated in the direction of the conductors 4 as is shown in FIG. 5.

In order to manufacture an upper panel plate 2, conductors 4 are placed in the grooves 12 of the rows of cores. As a result of the large number of cores in each row, the conductors 4 are held sufficiently rigidly in the grooves 12 so that the pressure plate 8 with the die 11 can be pressed upside down on an insulating panel plate 2 which is softened, for example, by heating. The conductors 4 in the panel plate 2 are embedded in the bottoms of the cavities 6 produced by the balls 9 serving as cores. The conductors 4 may be provided with cams 5 which project in the cavities 6. The walls of the cavities 6 are then covered with a luminescent material 13.

The lower panel plate 1 is provided with embedded strip-shaped conductors by pressing the conductors 3 in the softened material of the panel plate 1.

The upper surface of the conductors 3 is brought below the surface of the panel plate 1 by etching so that channels 7 are formed.

The panel plates 1 and 2 are then placed on each other, connected together in a vacuum-tight manner, the cavities 6 are evacuated and filled with a suitable gas atmosphere. if a suitable potentialdifference is applied between two conductors 3 and 4, a gas discharge will occur in the cavity situated at the point of intersection of said conductors, which gas' discharge, also due to the luminescent material 13 present on the wall of the'cavity 6, will be visible from the upper side of the plate 2 as a light spot.

The connection of the 'balls 9 in the holes of the pressure plate 8 may also be effected by forcing the balls in -holes smaller than the ball diameter of the pressure plate 8 as is shown in FIGS. 6 and 7. In this case also the balls are also welded or soldered since otherwise they may work loose when the grooves 12 are provided.

In FIG. 7 the balls 9 engage each other. The advantage is that when the balls 9 are forced in the panel is that the height of the cavities obtained therewith is arbitrary. The ready detachment of the cores after forcing them in a soft panel plate can be obtained by making the cylinders 14 from a material having a larger coefficient of thermal expension than that of the material of the panel plate.

The sticking of the insulating material of the panel plate to the cores can be avoided by covering the cores, prior to providing the conductors 4 in the grooves 12, with a thin powdered layer of, for example, oil, soot, graphite, aluminium oxide or another suitable material.

Of course the cores may also have other suitable shapes. For example, they may be conical or oval.

It is also possible to press the cores in a flat nonperforated pressure plate and welding them if the material of the cores is sufficiently hard in relation to the hardness of the material of the pressure plate.

What is claimed is:

'1. A method of manufacturing a gas discharge panel for the display of pictures, the discharge panel including an upper panel plate and a lower panel plate, each plate having a number of mutually insulated parallel strip-shaped conductors, the conductors of the lower panel plate intersecting the conductors of the upper panel plate at an angle, and also including a gas atmosphere which is provided between the panels, said method comprising the steps of:

immovably securing a plurality of cores in parallel rows in a pressure plate, said cores projecting beyond the surface of the plate;

providing a groove in the free end of each core, said grooves being oriented in the same direction in each row and being parallel to grooves in other rows;

placing strip-shaped conductors in each row of grooves in said cores;

softening the upper plate of the discharge panel, said upper plate consisting of light-pervious insulating material;

forcing the pressure plate with said strip-shaped conductors into said softened upper plate to deposit said strip-shaped conductors into said upper plate and to create cavities in said upper plate by said cores; and

separating said pressure plate from the upper panel plate, the conductors and cavities remaining in the upper plate.

2. The method of claim 1 also including the steps of:

making parallel channels in a second lower plate of the discharge panel, said lower plate consisting of an insulating material;

inserting strip-shaped conductors in said channels;

and

lowering the surface of each of the strips to be below the surface of said second lower plate.

3. The method of claim 2 also including the steps of:

placing the upper plate on the lower plate with said upper plate strips at an angle to said lower plate strips, said lowered strips of said lower plate forming channels which communicate with said cavities of said upper plate; and

sealing the upper and lower panel plates together.

4. The method of claim 1 wherein the strip-shaped conductors are provided with projections which extend from the upper plate after separation, into the cavities formed by the cores.

5. 'A method as claimed in claim 1 wherein the cores consist of balls, and the method includes the steps of insetting the balls in the pressure plate to approxiniately half of their diameter and securing them in said p ate.

6. A method as claimed in claim 1 wherein the cores consist of cylinders, and the method includes the steps of partly insetting the cylinders in the pressure plate and securing them in said plate.

7. A method as claimed in claim 1, including the step of providing luminescent material on the walls of the cavities. it t at a a 

1. A method of manufacturing a gas discharge panel for the display of pictures, the discharge panel including an upper panel plate and a lower panel plate, each plate havIng a number of mutually insulated parallel strip-shaped conductors, the conductors of the lower panel plate intersecting the conductors of the upper panel plate at an angle, and also including a gas atmosphere which is provided between the panels, said method comprising the steps of: immovably securing a plurality of cores in parallel rows in a pressure plate, said cores projecting beyond the surface of the plate; providing a groove in the free end of each core, said grooves being oriented in the same direction in each row and being parallel to grooves in other rows; placing strip-shaped conductors in each row of grooves in said cores; softening the upper plate of the discharge panel, said upper plate consisting of light-pervious insulating material; forcing the pressure plate with said strip-shaped conductors into said softened upper plate to deposit said strip-shaped conductors into said upper plate and to create cavities in said upper plate by said cores; and separating said pressure plate from the upper panel plate, the conductors and cavities remaining in the upper plate.
 2. The method of claim 1 also including the steps of: making parallel channels in a second lower plate of the discharge panel, said lower plate consisting of an insulating material; inserting strip-shaped conductors in said channels; and lowering the surface of each of the strips to be below the surface of said second lower plate.
 3. The method of claim 2 also including the steps of: placing the upper plate on the lower plate with said upper plate strips at an angle to said lower plate strips, said lowered strips of said lower plate forming channels which communicate with said cavities of said upper plate; and sealing the upper and lower panel plates together.
 4. The method of claim 1 wherein the strip-shaped conductors are provided with projections which extend from the upper plate after separation, into the cavities formed by the cores.
 5. A method as claimed in claim 1 wherein the cores consist of balls, and the method includes the steps of insetting the balls in the pressure plate to approximately half of their diameter and securing them in said plate.
 6. A method as claimed in claim 1 wherein the cores consist of cylinders, and the method includes the steps of partly insetting the cylinders in the pressure plate and securing them in said plate.
 7. A method as claimed in claim 1, including the step of providing luminescent material on the walls of the cavities. 